[mythtv-users] capture parameters suitable for DVD output

Michael T. Dean mtdean at thirdcontact.com
Mon Sep 25 06:56:15 UTC 2006

On 09/25/06 01:29, D. Hugh Redelmeier wrote:

>I'm setting up a Myth box.  I think that I want to use it like a DVD
>recorder with a hard disk.
>It was not obvious to me what the easiest way to burn DVDs from Myth
>might be.  I've settled on Myth Archive.  (Alternative recommendations
Stick with MythArchive.

>Myth Archive takes a very long time to
transcode a video to

> burn a DVD if the original
>recording was not in a resolution suitable for DVD.  As far as I can
>tell, suitable resolutions for NTSC are:
>	720x480
>	352x480
>and maybe
>	360x480

>	704x480

>	352x240

all as MPEG-2.

And, 352x240 (I know you said that), but this time as MPEG-1.

All of the above assuming NTSC.  Also, 16:9 aspect is not supported for 
any video with 352x(whatever) resolution.

>Which of these last three are considered proper resolutions for DVDs?

>What bitrates make sense?  I'd like to mimic the DVD recorders that we
>have.  They offer three quality choices: 2 hour, 4 hour, and 6 hour
>modes.  These choices select the resolution and the bandwidth.
>Myth offers choices for two aspects of bitrate: bitrate and maximum
Well, DVD's have a certain amount of storage.  Bitrate is expressed in 
some unit of storage per unit of time.  2 hours is a certain length of 
time.  Math is your friend.

Or, the help text on the control can be the friend you cheat off of:

Bitrate in kilobits/second.  2200Kbps is approximately 1 Gigabyte per hour.

Max. Bitrate
Maximum Bitrate in kilobits/second.  2200Kbps is approximately 1 
Gigabyte per hour.

(Note, though, that if you try to add "additional information" to make 
more accurate calculations, they'll probably be less exact because of 
subtle details of all the factors involved, so I recommend you do 
"back-of-the-envelope" calculations followed by real-life tests.)

>I'd like to know what to set all of these parameters to to get optimal
>pictures within the constraints of 2 hour, 4 hour, and 6 hour capacity
>for a single-layer DVD.
Variable bitrate doesn't translate to always 2-, 4-, or 6-hours.


>I'm using a Hauppauge PVR-150 with hardware MPEG-2.  I'd prefer not to
>transcode to DivX/Xdiv but maybe that would be worthwhile.
DVD spec won't allow MPEG-4--gotta be in MPEG-2, so if you transcode to 
MPEG-4 (DivX or XviD), you'll have to transcode back to burn.


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